Mailing List flyrotary@lancaironline.net Message #65051
From: RD Reyenga 85rotary7@gmail.com <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Curved aluminum radiators.
Date: Thu, 22 Aug 2019 14:18:42 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Fair comment about using all the available power however, my GSXR 750 never goes above 80C with sustained power use. More importantly, at idle when there is no external airflow, the heat rises quickly to close to the boiling point. The tiny thermally activated fan is remarkably good at generating just enough flow through the curved radiator to keep the heat down. My assessment is that Suzuki has optimized the curved rad, frontal area, cowling and fan quite well so there is merit in assessing it for our rotary engine use. I'm restoring a Suzuki RE5 rotary and intend to try out curved radiators and cowling vs the massive rectangular radiator Suzuki designed in 1975.

Dave

On Thu, Aug 22, 2019 at 1:33 PM Ernest Christley echristley@att.net <flyrotary@lancaironline.net> wrote:
There bikes can make 200Hp, but how long can a rider use the power? The small radiator requirements may be deceptive.


On Thu, Aug 22, 2019 at 11:29 AM, jay bendlin drhyed@yahoo.com
I think if you start exploring motorcycle cooling you may find some solution. Most sportbikes have been making 120-200+ hp for 20 years now and most use curved rads, and many sport touring and endro type bikes have unique cooling solutions, if you start doing google image searches you will probably find ideas left and right. I had a Honda RC-51 that used very small (in my opinion) side-mounted radiators, you could also look at Honda VFR radiators (came in several engines sizes 750-800), also small side mounts but they were not curved. Its amazing how much horsepower can be cooled with such small frontal area, but that's where engineers earn their keep.  

On Thursday, August 22, 2019, 10:44:58 AM EDT, Rob McMillan robmcmillanpls@gmail.com <flyrotary@lancaironline.net> wrote:


$148 to cut one open would suck, but might it be worth knowing before getting 2 more and doing a bunch of ducting...

On Thu, Aug 22, 2019, 2:32 AM Todd Bartrim bartrim@gmail.com <flyrotary@lancaironline.net> wrote:
I'm considering making some changes to my cooling system as it is not adequate when flying low & slow, as on recent flights on a few hot days. I'm still using a set of evap cores as they fit the limited space on either side of the PSRU in an RV cowl.
  Bill Jepson made mention of a curved radiator earlier this summer, which as been simmering on a hot spot way back in my brain ever since. I've spent the last few days looking real hard at the idea.
The size and shape of the curve looks like it would conform quite nicely to the bottom of the RV cowl. so that the top of the rad would be perpendicular to the airflow while the bottom will curve away. This would require a new ducts to be glassed to take advantage of this, but that would allow for more time and room to slow down the airflow for greater efficiency. It would also almost double the square inches of cooling area than I currently have, however as it is thinner it would provide half of the cubic inches of volume as I currently have.
 The small thick rads I currently use were chosen more with high speeds in mind (well, and of course ease of installation), but now I'm thinking that I'd rather have a thinner rad that would perform better on the ground and in slow flight. These curved rads seem like they could offer some advantages.
  I've just found them listed on Amazon.ca for $148CAD with free shipping (x2)which seems pretty resonable, so for $300, it might offer a significant cooling upgrade.... or maybe not.
I wish I could find an old one to cut open to inspect, test weld, check for fit, etc.

Does anybody have any thoughts on the idea? I'm on the edge so it wouldn't take much to push me over, or pull me back....

Todd Bartrim
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